Measurement of myoglobin oxygen saturation in the presence of hemoglobin interference by near-infrared spectroscopy

Abstract

Spectroscopic measurement of myoglobin oxygenation has been made in the presence of hemoglobin using visible light. Although the spectral changes with oxygen binding are smaller, near infrared wavelengths have deeper tissue penetration. This offers an attractive means for making noninvasive muscle oxygenation measurements. Visible and near-infrared spectra of myoglobin with decreasing oxygen saturation in the presence of both oxyhemoglobin and deoxyhemoglobin were obtained. Fractional oxygen saturations were determined from the visible region. The near-infrared spectra were divided into calibration and test sets and analyzed by the method of multiple linear regression. Baseline offsets were reduced by preprocessing the data using spectral second derivatives to enhance the significant features of the spectra. This method of analysis demonstrated good correlation of the near- infrared spectra with the calibration saturation data. These results show that myoglobin oxygen saturation measurements in vitro can be made in the presence of hemoglobin as an interferant, using near-infrared spectroscopy.